JP2003183327A - Norbornene copolymer for photoresist, method for producing the same, and photoresist composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a norbornene copolymer for photoresists, to provide a method for producing the same, and to provide a photoresist composition containing the same. <P>SOLUTION: The norbornene copolymer for photoresists is synthesized by using 5-norbornen-2-alkane-1,3-dione and a norbornene derivative as the essential comonomers, and selectively adding thereto a ketal compound being a derivative of the 5-norbornen-2-alkane-1,3-dione compound. A photoresist composition containing the copolymer is also provided. According to this, it not only has a high transparency to 193 nm and etching resistance but also is controllable in its pKa, so that the resolution can be heightened owing to the marked difference between the dissolution rates at exposed and unexposed areas. Because it has a highly hydrophilic diketone functional group, it can exhibit excellent adhesion to substrates and can be very usefully used as an ArF photoresist material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a norbornene-based copolymer for photoresist, a method for producing the same, and a photoresist composition containing the same. More specifically, the present invention relates to a phenol group having a pKa of about 10 and a pKa of about 5. A 5-norbornene-2-alkane-1,3-dione compound having a value between the carboxyl groups and a norbornene derivative are used as an essential comonomer, and the 5-norbornene-2-alkane-1,3 is selectively used. The present invention relates to a novel norbornene-based copolymer synthesized by adding a ketal compound, which is a derivative of a dione compound, and a photoresist composition containing the same.

[0002]

2. Description of the Related Art Generally, a photoresist for producing a fine pattern must have a low light absorption at a wavelength of 193 nm, an excellent etching resistance, a heat resistance and an adhesive property. The one that can be developed in the applied 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution is advantageous in terms of reduction of process cost. However, it is extremely difficult to synthesize a photoresist that completely satisfies these characteristics.

Therefore, most of the studies to date have been 193
It has been focused on synthesizing a resin having a high transmittance at a wavelength of nm and an excellent etching resistance. For example, ArF
Acrylic acid derivatives and methacrylic acid derivatives, which have been mainly used as basic monomers of photoresist materials for
Although it has excellent resolution, it has a fatal drawback that the photosensitive film cannot function as a mask because of poor etching resistance. In order to solve such a drawback, a study of introducing an alicyclic olefin unit into the side chain and main chain of an acrylic copolymer is conducted, and the alicyclic olefin unit is introduced into the main chain. As a result, the etching resistance of the ArF resin was successfully increased. However, this shows a high acidity of about 5 pKa since the carboxyl group is used as a soluble group, and the dissolution rate in an alkaline developer is higher than that of a KrF photoresist in which a phenol group of about 10 pKa is used as a soluble group. Therefore, when forming a fine pattern, there is a problem that a top loss is formed in which the upper part of the pattern is rounded, which is large. Moreover, since the carboxyl group has a strong adhesive force with TMAH and causes swelling, the pattern is not firmly formed, and if the developer currently used is used without being diluted, the unexposed portion is dissolved. Therefore, an excellent pattern cannot be obtained. Therefore, in order to solve such a problem, a study was conducted to introduce a ketal group of a ketoester into a photoresist for ArF, which has a pKa of 11 or more and is inferior in sensitivity in a TMAH solution and is suppressed in dissolution rate. In addition, the pKa of the ketoester group is too high to be well developed during development in a TMAH solution, and as the mole fraction of the substituted ketoester group increases, the hydrophilicity of the resin itself becomes poorer and the adhesive force is weakened. There was a problem that the pattern collapsed or separated during formation.

[0004]

SUMMARY OF THE INVENTION Therefore, in order to solve the above-mentioned problems of the prior art, the present invention provides a photoresist for photoresist having a value of between about 10 phenol groups of pKa and about 5 carboxyl groups of pKa. By developing a polymer, it is intended to provide a photoresist composition capable of forming a pattern profile which is stable and has excellent resolution and adhesion to a substrate.

[0005]

The first aspect of the present invention is to provide 5-norbornene-2-alkane-1, of the following general formula (1b),
Provided are 3-dione derivatives.

[0006]

[Chemical 10]

[Wherein R ₁ is a linear group having 1 to 12 carbon atoms,
A branched or cyclic alkyl group; R ₂ is a hydrogen atom,
Or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms; R ₃ , R ₄ and R ₅ are each independently a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms. R ₁ and R ₅ can be linked to each other to form a cyclic diketone; R ₆ and R ₇ are each independently a carbon number of 1 to 1;
6 alkyl groups which may be linked together to form a ring; p is an integer from 0-6. The second aspect of the present invention is a 5-norbornene-2-alkane-1, represented by the following general formula (1a), in the presence of an acid catalyst in an organic solvent.
5-Norbornene-2-alkane-1,3 of the general formula (1b), which comprises a step of transketalizing a 3-dione compound with a cyclic ketal or a cyclic acetal compound.
-Providing a method for producing a dione derivative.

[0008]

[Chemical 11]

[In the formula, R _{1 to} R ₅ and p have the same meanings as defined above. The third aspect of the present invention provides a norbornene-based copolymer for photoresist represented by the following general formula (3).

[0010]

[Chemical 12]

[Wherein R₁Is a C1-C12 linear, minute
A branched or cyclic alkyl group; R₂Is a hydrogen atom,
Or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms
And R₃, R_FourAnd R_FiveAre each independently a hydrogen atom,
Or a linear or branched alkyl group having 1 to 6 carbon atoms
R₁And R_FiveAre linked together to form a cyclic diketone.
Can be done; R₆And R₇Each independently has 1 to 6 carbon atoms
Alkyl groups that combine with each other to form a ring
Is possible; p is an integer of 0 to 6; R₈And R₉Is each
Each independently a hydrogen atom, or a linear or
Is a branched alkyl group, or-(CH₂)_qC (O) OR
_Ten,-(CH₂)_q-OR_Ten,-(CH ₂)_q-C (O) R
_Ten,-(CH₂)_q-OC (O) R_Ten,-(CH₂)_q-O
C (O) OR_TenOr- (CH₂)_q-C (O) OCH₂
OR_Ten(Where R_TenIs a hydrogen atom or 1 to 10 carbon atoms
Is a linear, branched or cyclic alkyl group, and q is 0 to
It is an integer of 6. ) And said R₈And R₉Are connected to each other
Can be joined to form a ring; a, b and c are
0.01 ≦ a / a + b + c ≦ 0.30, 0 ≦ b / a respectively
+ B + c ≦ 0.50 and 0.20 ≦ c / a + b + c ≦
A value satisfying 0.99; l, m and n are each
Independently 0 or 1. ] A fourth aspect of the present invention is the compound of the general formula (3) including the following steps.
A method for producing a norbornene-based copolymer for photoresist
provide. (A) If the palladium (II) catalyst is used as a polymerization catalyst in water
Or an organic solvent or a mixed solvent of water and an organic solvent
Dissolving step; (B) The catalyst solution is added to the 5-nor of the general formula (1a).
Bornene-2-alkane-1,3-dione compounds and
In addition to the norbornene derivative of the following general formula (2), selection
5-norbornene-2-al of the general formula (1b)
Adding the can-1,3-dione derivative as a comonomer,
Steps of reacting under an inert gas atmosphere or under reduced pressure:

[0012]

[Chemical 13]

[Wherein, R ₈ and R ₉ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, or — (CH ₂ ) _q C (O) OR ₁₀ , -(CH
₂ ) _q- OR ₁₀ ,-(CH ₂ ) _q -C (O) R ₁₀ ,-(CH
_{2) q -OC (O) R} 10, - (CH 2) q -OC (O) OR
₁₀ or _{- (CH 2) q -C (} O) OCH 2 OR 10 ( wherein, R ₁₀ is a hydrogen atom or a C 1-10 linear, a branched or cyclic alkyl group, q is 0 R ₈ and R ₉ may be connected to each other to form a ring. The fifth aspect of the present invention is (a) the copolymer represented by the general formula (3);
There is provided a photoresist composition containing (b) a photo-acid generator; and (c) an organic solvent capable of dissolving the components (a) and (b).

The sixth aspect of the present invention provides a method for forming a photoresist pattern, which comprises the steps of: (a) applying the photoresist composition to the top of an etching layer to form a photoresist film. (B) prebaking the photoresist film on a high-temperature substrate; (c) placing a mask on the prebaked photoresist film and exposing it to a light source having a wavelength of 250 nm or less. (D) baking the exposed photoresist film on a high temperature substrate; and (e) developing the baked photoresist film to obtain a desired photoresist pattern.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The 5-norbornene-2-alkane-1,3-dione derivative of the present invention will be described in detail below.

The 5-norbornene-2-alkane-1,3-dione derivative of the present invention is a kind of ketal compound having the structure of the following general formula (1b):

[0017]

[Chemical 14]

[Wherein R ₁ is a linear group having 1 to 12 carbon atoms,
A branched or cyclic alkyl group; R ₂ is a hydrogen atom,
Or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms; R ₃ , R ₄ and R ₅ are each independently a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms. R ₁ and R ₅ can be linked to each other to form a cyclic diketone; R ₆ and R ₇ are each independently a carbon number of 1 to 1;
6 alkyl groups which may be linked together to form a ring; p is an integer from 0-6. The 5-norbornene-2-alkane-1,3-dione derivative can be synthesized by the following two methods.
One of them is to transketalize a 5-norbornene-2-alkane-1,3-dione compound having the structure of the following general formula (1a) in an organic solvent in the presence of an acid catalyst with a cyclic ketal or a cyclic acetal compound. It is a method to let.

[0019]

[Chemical 15]

[Wherein R ₁ is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms; R ₂ is a hydrogen atom, or a linear, branched or cyclic group having 1 to 6 carbon atoms] An alkyl group; R ₃ , R ₄ and R ₅ are each independently a hydrogen atom,
Alternatively, it is a linear or branched alkyl group having 1 to 6 carbon atoms, and R ₁ and R ₅ can be linked to each other to form a cyclic diketone; p is an integer of 0 to 6. The acid catalyst that can be used for the transketalization is camphorsulfonic acid, p-toluenesulfonic acid, pyridinium p
-Including organic acids such as toluene sulphonate, oxalic acid or pyridinium chloride; and inorganic acids such as hydrochloric acid, sulfuric acid or nitric acid. The addition amount of these acid catalysts is appropriately determined without limitation, but is preferably in the range of 0.1 to 10 mol% with respect to the 5-norbornene-2-alkane-1,3-dione compound. Selected in.

The organic solvent usable for the transketalization includes hydrocarbons such as benzene, toluene, xylene, cyclohexane, n-hexane and n-octane; methylene chloride, dichloroethane, trichloroethylene, carbon tetrachloride and chloroform. Halogenated hydrocarbons such as; methyl acetate, ethyl acetate, n
Esters such as butyl acetate and methyl propionate; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and t-butanol; dimethyl ether, diethyl ether, diisopropyl ether, dimethoxyethane, tetrahydrofuran. And ethers such as dioxane; N-methylpyrrolidone, N,
Including N-diethylformamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, etc., one of these solvents may be used alone, or two or more thereof may be mixed and used. May be.

Examples of the cyclic ketal compound include 2,2-dimethyl-1,3-dioxolane and 1,4
-Dioxaspiro- [4.5] decane, 6,10-dioxaspiro- [4.5] decane, 2,2-dimethyl-
1,3-dioxane, 2,2-diethyl-1,3-dioxane and the like can be mentioned. On the other hand, examples of the cyclic acetal compound include 1,3-dioxolane, 1,3-dioxane, 2-ethyl-1,3-oxolane and 2-ethyl-1,3-dioxane. The amount of the ketal or acetal compound used is selected in the range of 1 to 5 times the molar amount of the 5-norbornene-2-alkane-1,3-dione.

In the transketalization reaction,
The reaction temperature is not particularly limited, but is usually 0 to 150 ° C,
It is preferably selected in the range of 20 to 100 ° C. Also,
The reaction time varies depending on the kind and concentration of the compound and other reaction conditions, but it is usually preferable to select it in the range of 1 to 10 hours.

The transketalization method according to the present invention comprises:
In the case of a general ketalization reaction which will be described later, a side reaction due to water produced as a by-product can be avoided, and there is an advantage that the yield is high.

The 5-norbornene-2-alkane-
The second method for synthesizing the 1,3-dione derivative is a 5-norbornene-2-alkane-1,3-of the above general formula (1a) in the presence of an acid catalyst and, if necessary, a suitable organic solvent.
The ketalization of dione compounds using alkyl alcohols or alkane diols.

The acid catalyst usable for the ketalization is an organic acid such as camphorsulfonic acid, p-toluenesulfonic acid or pyridinium p-toluenesulfonate;
And inorganic acids such as hydrochloric acid, sulfuric acid or phosphoric acid. The addition amount of such an acid catalyst is appropriately determined without particular limitation, but is usually 0.1 with respect to the 5-norbornene-2-alkane-1,3-dione compound.
-20 mol%, preferably 1-10 mol% is selected.

The organic solvents usable for the ketalization include hydrocarbons such as toluene, xylene, benzene, cyclohexane, n-hexane and n-octane; methylene chloride, dichloroethane, trichloroethylene, carbon tetrachloride and chloroform. Halogenated hydrocarbons such as methyl acetate, ethyl acetate, n-
Esters such as butyl acetate and methyl propionate; ethers such as dimethyl ether, diethyl ether, diisopropyl ether, dimethoxyethane, tetrahydrofuran and dioxane; N-methylpyrrolidone, N, N-dimethylformamide, N, N-
It includes dimethylacetamide, dimethylsulfoxide, and the like, and one of these solvents may be used alone, or two or more thereof may be mixed and used. Preferably, during the ketalization reaction, it is preferable to use a solvent that can easily remove water from the reaction system by forming an azeotropic mixture with water in the reaction mixture.

Further, the alkyl alcohol which can be used for the ketalization includes methanol, ethanol, propanol, butanol, pentanol, hexanol and the like, and the alkane diol includes ethylene glycol, propylene glycol and 2,2-dimethyl. Propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, tri Included are ethylene glycol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, and the like. The amount of alcohol or diol used is appropriately adjusted without any particular limitation.
-The amount of norbornene-2-alkane-1,3-dione is usually 1 to 20 mol times, preferably 1.5 to 1
It is selected in the range of 0 mol times.

In the ketalization reaction, the reaction temperature is not particularly limited, but is usually selected in the range of 0 to 150 ° C, preferably 20 to 130 ° C.

After completion of the transketalization or ketalization reaction as described above, the resulting ketal compound may be used directly in the polymerization reaction without further purification or separation steps and is known in the art. It may be used in the polymerization after extraction, recrystallization, or isolation and purification by any other suitable method.

On the other hand, the 5-norbornene-2-alkane-1,3-dione compound of the general formula (1a) used for the production of the ketal compound of the present invention is sodium alkoxy and, if necessary, the presence of a suitable solvent. Underneath, acetyl norbornene can be prepared by reacting with ethyl alkanoate. At this time, the amount of ethylalkanoate used is not particularly limited, but is usually 1 to 30 mol times, preferably 1 to 30 times, that of acetylnorbornene.
It is appropriately selected in the range of 10 times by mole.

The norbornene-based copolymer for photoresist of the present invention will be described in detail below.

The norbornene-based copolymer for photoresists of the present invention has the structure of the following general formula (3), and the alicyclic group is present in the main chain.

[0034]

[Chemical 16]

[Wherein R₁Is a C1-C12 linear, minute
A branched or cyclic alkyl group; R₂Is a hydrogen atom,
Or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms
And R₃, R_FourAnd R_FiveAre each independently a hydrogen atom,
Or a linear or branched alkyl group having 1 to 6 carbon atoms
R₁And R_FiveAre linked together to form a cyclic diketone.
Can be done; R₆And R₇Each independently has 1 to 6 carbon atoms
Alkyl groups that combine with each other to form a ring
Is possible; p is an integer of 0 to 6; R₈And R₉Is each
Each independently a hydrogen atom, or a linear or
Is a branched alkyl group, or-(CH₂)_qC (O) OR
_Ten,-(CH₂)_q-OR_Ten,-(CH ₂)_q-C (O) R
_Ten,-(CH₂)_q-OC (O) R_Ten,-(CH₂)_q-O
C (O) OR_TenOr- (CH₂)_q-C (O) OCH₂
OR_Ten(Where R_TenIs a hydrogen atom or 1 to 10 carbon atoms
Is a linear, branched or cyclic alkyl group, and q is 0 to
It is an integer of 6. ) And said R₈And R₉Are connected to each other
Can be joined to form a ring; a, b and c are
0.01 ≦ a / a + b + c ≦ 0.30, 0 ≦ b / a respectively
+ B + c ≦ 0.50 and 0.20 ≦ c / a + b + c ≦
A value satisfying 0.99; l, m and n are each
Independently 0 or 1. ] The molecular weight of the norbornene-based copolymer is not particularly limited.
The weight average molecular weight is usually 1,000 to 300,0.
00, preferably 1,500 to 100,000, and
It is preferably 1,500 to 30,000.

According to the present invention, in the synthesis of the norbornene-based copolymer, the compound represented by the general formula (1) is used as an essential comonomer.
The 5-norbornene-2-alkane-1,3-dione compound of a) and the norbornene derivative of the following general formula (2) are used, and in addition to this, 5-norbornene-2-alkane-1, The ketal compound of the above general formula (1b), which is a derivative of a 3-dione compound, can be further used.

[0037]

[Chemical 17]

[Wherein, R ₈ and R ₉ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, or — (CH ₂ ) _q C (O) OR ₁₀ , -(C
_{H 2) q -OR 10, -} (CH 2) q -C (O) R 10, - (C
_{H 2) q -OC (O)} R 10, - (CH 2) q -OC (O) O
R ₁₀ or - (CH ₂₎ at _{q -C (O) OCH 2 OR} 10 ( wherein, R ₁₀ is a hydrogen atom or a C 1-10 linear, branched or cyclic alkyl group, q is 0 Is an integer of ˜6), and R ₈ and R ₉ may be connected to each other to form a ring. The norbornene derivative of the general formula (2) used for synthesizing the copolymer of the present invention can be synthesized, for example, by the Diels-Alder reaction of cyclopentadiene and an appropriately substituted parent diene, and the general reaction formula is as follows. Is.

[0039]

[Chemical 18]

[In the formula, R ₈ and R ₉ have the same meanings as defined in the general formula (2). Specific examples of the norbornene derivative useful in the present invention include norbornene, norbornenemethanol, norbornenecarboxylic acid, 5-norbornene-2-ethoxymethylcarboxylate, t-butyl-5-norbornene-2-carboxylate, and dinorbornene. -T-butyl-5-norbornene-2-dicarboxylate, methyl-5-norbornene-2-carboxylate, isobornyl-5-norbornene-2-carboxylate, 2-hexyl-5-
Norbornene, 5-norbornene-2-methanol, 5
-Norbornen-2-ol, 5-norbornen-2,
Examples include, but are not limited to, 3-dimethanol, and 5-oxa-tricyclo [5.2.1.0 (2.6)] dec-8-en-3-one.

The polymerization method for obtaining the norbornene-based copolymer of the present invention includes radical polymerization, cationic polymerization, addition polymerization, and opening for obtaining ordinary polycyclic polymers including norbornene and its derivatives. Although all polymerization techniques such as ring polymerization can be used, addition polymerization using a palladium (II) compound as a polymerization catalyst is preferably used, for example, as shown in the following reaction formula (2). .

[0042]

[Chemical 19]

At this time, the palladium (II) catalyst is represented by the following general formula (4a), (4b) or (4c).

[0044]

[Chemical 20]

[0045]

[Chemical 21]

[0046]

[Chemical formula 22]

[In the formulas (4a) to (4c), X
Is a halogen atom or an alkyl group having 1 to 10 carbon atoms; R'is an allyl compound having 3 to 20 carbon atoms; R "
Is a nitrile compound or a cyclodiene compound; n
Is 1 or 2. The cyclodiene compound is a cyclic alkanedienyl group, an indenyl group, a fluorenyl group, or a derivative thereof represented by the following general formulas (a) to (d).

[0048]

[Chemical formula 23]

[In the formulas (a) to (d), R ₁ to
R ₁₆ is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cyclic alkyl group, or an alkoxy group, or an allyl group or an allyl alkyl group having 6 to 20 carbon atoms, f
Is an integer of 4-8. The method for producing the norbornene-based copolymer of the present invention will be described more specifically. First, the palladium (II) catalyst represented by the general formulas (4a) to (4c) is used as a polymerization initiator in water or an appropriate organic solvent, Alternatively, after dissolving in a mixed solvent of water and an organic solvent, the monomer of the general formula (1a) and the monomer of the general formula (2) are added to the catalyst solution, and the general formula is selectively added. After further adding the monomer of (1b), under an inert gas atmosphere or under reduced pressure, -50 to 8
The reaction is carried out at 0 ° C for 0.5 to 48 hours. After the reaction is complete, the resulting polymer can be applied for purification by known methods for purification.

Water or an organic solvent, or a mixed solvent of water and an organic solvent can be used as a polymerization solvent in the above-mentioned polymerization reaction. At this time, the organic solvent is an ether such as ethyl ether, 1,2- Dimethoxyethane, tetrahydrofuran, 1,4-dioxane or 1,3-dioxolane; ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetone or cyclohexanone; esters such as methyl acetate, ethyl acetate or n-butyl acetate; and hydrocarbons such as benzene. , Toluene or xylene may be used alone or in combination.

The feature of the novel norbornene-based copolymer of the present invention produced by the above-mentioned method is that the copolymer contains the monomer represented by the general formula (1a).
That is, 5-norbornene-2-of the general formula (1a)
The diketone group of the alkane-1,3-dione compound is higher than the acidity of the phenolic hydroxy group, which is the soluble group of the novolac resin and the phenol resin used so far, and is usually a carboxyl group that acts as the soluble group of the photoresist for ArF. Since the pKa value is lower than the acidity of the group, it is 2.38 mass% TMA which is an ordinary alkaline developer.
The dissolution rate at the time of development is easily adjusted with the H 2 aqueous solution, and therefore, top loss and swelling of the photoresist are prevented, and excellent resolution is obtained. Furthermore, the diketone group present in the non-exposed region increases the hydrophilicity of the copolymer and improves the adhesive force to the substrate, and thus an excellent photoresist pattern can be provided. Therefore, the norbornene-based copolymer of the present invention is extremely useful as a deep UV photoresist material using a wavelength of 250 nm or less.

Particularly, the copolymer of the present invention has the general formula (1)
When the monomer represented by b) is further contained, the ketal introduced as a protective group is eliminated by the action of the acid generated during exposure to provide an additional diketone group. The general formula (1b) having a protected diketone group is used without using only the monomer of the general formula (1a) as a monomer providing a diketone group to the copolymer of the present invention.
When the monomer of is further used, the rate of elimination by acid can be adjusted, and the acidity after elimination can be adjusted, so that the resolving power can be enhanced by the remarkable difference in dissolution rate between the exposed and unexposed areas. It is even more advantageous in the aspect.

Next, the photoresist composition of the present invention and the method for forming a photoresist pattern using the composition will be described in detail as follows.

The photoresist composition of the present invention comprises (a)
The novel norbornene-based copolymer for photoresist,
(B) a photo-acid generator, and (c) a solvent capable of dissolving the component (a) or (b).

The photo-acid generator used for producing the photoresist composition of the present invention includes triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorooctanesulfonate, diphenyl-.
p-tolylsulfonium perfluorooctane sulfonate, tris (p-tolyl) sulfonium perfluorooctane sulfonate, tris (p-chlorobenzene)
Sulfonium trifluoromethanesulfonate, tris (p-tolyl) sulfonium trifluoromethanesulfonate, trimethylsulfonium trifluoromethanesulfonate, dimethylphenylsulfonium trifluoromethanesulfonate, dimethyltolylsulfonium trifluoromethanesulfonate, dimethyltolylsulfonium perfluorooctanesulfonate, triphenylsulfonium p-toluenesulfonate , Triphenylsulfonium methanesulfonate, triphenylsulfonium butanesulfonate, triphenylsulfonium n-octanesulfonate, triphenylsulfonium 1-naphthalene sulfonate, triphenylsulfonium 2-naphthalene sulfonate, triphenylsulfonium 10-can Sulfonate, triphenylsulfonium 2,5-dichlorobenzenesulfonate, diphenyltolylsulfonium 1,3,4-trichlorobenzenesulfonate, dimethyltolylsulfonium p-toluenesulfonate, diphenyltolylsulfonium 2,5-dichlorobenzenesulfonate, 1-cyclohexylsulfonyl -1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis (1-methylethylsulfonyl) methane, bis (cyclohexylsulfonyl)
Diazomethane, 1-cyclohexylsulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1
-Cyclohexylsulfonyl-3,3'-dimethylbutan-2-none, 1-diazo-1-methylsulfonyl-4
-Phenylbutan-2-none, 1-diazo-1- (1,
1-dimethylethylsulfonyl) -3,3-dimethyl-
2-butanone, 1-acetyl-1- (1-methylethylsulfonyl) diazomethane and the like can be used. The content of the photo-acid generator is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the copolymer resin.

The organic solvent used for producing the photoresist composition of the present invention includes ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether,
Diethylene glycol monoethyl ether, propylene glycol methyl ether acetate, propylene glycol propyl ether acetate, diethylene glycol dimethyl ether, ethyl lactate, toluene, xylene, methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, or a mixed solvent thereof is used. can do. If necessary, in addition to the organic solvent, N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-, as an auxiliary solvent.
Methylpyrrolidone, dimethyl sulfoxide, alcohols and the like can be used in combination. At this time, the content of the auxiliary solvent in the total solvent is preferably 10% by mass or less, and the total solvent content of the entire composition is 70-9.
5 mass% is preferable.

The photoresist composition of the present invention is usually
A novel copolymer of the present invention, a photoacid generator, and a three-component organic solvent, and optionally a UV absorber,
It may further include a sensitivity adjusting agent which is a basic substance, a plasticizer, an organic acid and a surfactant.

The method of forming a photoresist pattern using the photoresist composition of the present invention is as follows.
It looks like this: First, the photoresist composition of the present invention is applied on the top of an etching layer such as a silicon wafer, and then prebaked on a high temperature substrate at 60 to 150 ° C. for 60 to 180 seconds to form a photoresist film.
Next, a mask is placed on the photoresist film to form a pattern, and ArF excimer laser light having a wavelength of 250 nm or less is irradiated at an amount of 1 to 100 mJ / cm ² , and then a high temperature substrate of 60 to 150 ° C. Above 60 ~
Bake for 180 seconds. Then 0.1 to 5 mass%
A photoresist pattern is formed by developing using a developing solution such as an aqueous solution of tetraammonium hydroxide (TMAH) for 30 to 180 seconds by a dipping method, a puddle method, a spraying method and other conventional methods.

[0059]

The present invention will be described in more detail based on the following examples, but the examples described below are merely illustrative of the present invention, and the present invention is not limited to these examples.

In the production examples and examples described later, the weight average molecular weight and the molecular weight distribution of the polymer are GPC (Gel Permeation) using polystyrene as a standard.
Chromatography: gel permeation chromatography, solvent: THF).

Production Example 1: Synthesis of 5-norbornene-2-butane-1,3-dione (NBDO) In a nitrogen atmosphere, 176.22 g (2 m) of ethyl acetate was obtained.
ol) and sodium methoxy (NaOMe) 108.
After dissolving 04 g (2 mol) in 1.5 L of THF, 136.19 g (1 mol) of 2-acetyl-5-norbornene was gradually added over 1 hour using a dropping funnel, and then reacted at room temperature for 24 hours. It was After the reaction was completed, the residual reaction product was extracted with water and ethyl acetate, and the product was separated by acid treatment. The separated product layer was washed with water three times or more and then dried over anhydrous magnesium sulfate. After removing the solvent by distillation, the product was distilled under reduced pressure to give 5-norbornene-2-butane-
125 g of 1,3-dione (yield 70%) was obtained.

Boiling point: 90 to 92 ° C./1 mmHg Production Example 2-1: 5-norbornene-2-{(3-ethylenedioxy)}-butan-1-one (hereinafter referred to as “NED
Synthesis of "OBO"): Method 1 (Transketalization) 35.6 g (200 mmol) of 5-norbornene-2-butane-1,3-dione obtained in Production Example 1 was dissolved in 200 ml of benzene to give 2, 2-dimethyl-1,3
-Dioxolane 61.28 g (600 mmol) and p-toluenesulfonic acid monohydrate 0.38 g
After adding (2 mmol), the mixture was reacted under reflux for 4 hours. After the reaction was completed, the reaction solution was washed with a 1M sodium hydroxide solution and water successively and then dried over anhydrous magnesium sulfate. After removing the solvent by distillation, the product was distilled under reduced pressure to obtain 177.6 g of 5-norbornene-2- (3-ethylenedioxy) -butan-1-one (yield 8
0%).

Production Example 2-2: 5-Norbornene-2-
Synthesis of {(3-ethylenedioxy)}-butan-1-one (hereinafter referred to as "NEDOBO"): Method 2 (ketalization) 5-norbornene-2-butane-1, obtained in Production Example 1 above 35.6 g (200 mmol) of 3-dione was dissolved in 200 ml of toluene, and ethylene glycol 37.
After adding 2 g (600 mmol) and 0.38 g (2 mmol) of p-toluenesulfonic acid monohydrate, water as a by-product was refluxed under a water separator.
The reaction was carried out for 6 hours while being removed by the (tack). After the reaction was completed, the reaction solution was washed with a 1M sodium hydroxide solution and water successively and then dried over anhydrous magnesium sulfate. After removing the solvent by distillation, the product was distilled under reduced pressure to obtain 31.08 g (yield 70%) of 5-norbornene-2- (3-ethylenedioxy) -butan-1-one.

Production Example 3-1: 5-Norbornene-2-
{(3-Propylenedioxy) -butan-1-one}
Synthesis of (hereinafter referred to as "NPDOBO"): Method 1
(Transketalization) 1,2-Dimethyl-1,3-dioxolane was replaced with 1,
5-Norbornene-2-{(3-propylenedioxy) -butan-1-one was prepared in the same manner as in Preparation Example 2-1, except that 52.87 g (600 mmol) of 3-dioxane was used. } 200.6 g (yield 85%)
Got

Production Example 3-2: 5-Norbornene-2-
{(3-Propylenedioxy) -butan-1-one}
Synthesis of (hereinafter referred to as "NPDOBO"): Method 2
(Ketalization) 1,3-instead of ethylene glycol as a diol
5-Norbornene-2-{(3-propylenedioxy) -butan-1-one} was prepared in the same manner as in Preparation Example 2-2 except that 45.66 g (600 mmol) of propanediol was used. 165 g (yield: about 70
%) Was obtained.

Production Example 4: 5-Norbornene-2-
{(2 ', 2'-dimethyl-3-propylenedioxy)
-Butan-1-one} (hereinafter referred to as "NDMPDOBO") as a synthetic diol, 2,2-dimethyl-1,3-propanediol 62.5 instead of 1,3-propanediol
5-Norbornene-2 was prepared in the same manner as in Preparation Example 3-2 except that g (600 mmol) was used.
-{(2 ', 2'-dimethyl-3-propylenedioxy) -butan-1-one} 158.4 g (yield: about 60
%) Was obtained.

Example 1: Poly [NCA: NEM
C: NBDO] = 1: 8: 1 (mass ratio) under a synthetic nitrogen atmosphere, 0.3 g of palladium chloride in water: TH
After being dissolved in a mixed solvent of F = 1: 1, 5-norbornene-2-carboxylic acid (hereinafter, referred to as a comonomer in the solution)
27 g of "NCA") and 3 g of 5-norbornene-2-butane-1,3-dione (hereinafter referred to as "NBDO") obtained in Preparation Example 1 were added, and the pressure in the reactor was reduced. Then, the mixture was reacted at about 40 ° C. for 24 hours. After the reaction was completed, the reaction solution was diluted with an appropriate amount of THF solvent to remove the palladium catalyst, and then stirred for about 5 hours while bubbling hydrogen gas, and the black precipitate formed at this time was filtered. Removed. The filtrate is poured into distilled water to precipitate, then filtered and dried to Pol.
y [NCA: NBDO] = 9: 1 (mass ratio) 25.5 g
(Yield 85%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 2,200 and 1.36, respectively.

Under a nitrogen atmosphere, the Poly [N
CA: NBDO] = 9: 1 (30 g) was dissolved in a THF solvent, 19.4 g of triethylamine and 16.5 g of chloromethylethyl ether were sequentially added to the solution, and the mixture was reacted at 0 ° C. for 4 hours. After the reaction is completed, the reaction solution is precipitated in distilled water, filtered and dried to obtain Po.
ly [NCA: NEMC: NBDO] = 1: 8: 1 (mass ratio) (yield 90%) was obtained. "NEMC" is 5-norbornene-2-ethoxymethylcarboxylate. The weight average molecular weight and the molecular weight distribution of the copolymer were 4,000 and 1.55, respectively.

Example 2: Poly [NCA: NEM]
C: NBDO] = 1.5: 7.5: 2 (mass ratio) 5-norbornene-2-carboxylic acid 2 as a comonomer
4 g and 5-norbornene-2-obtained in the above Production Example 1
Poly [NCA: N was prepared in the same manner as in Example 1 except that 6 g of butane-1,3-dione was used.
BDO] = 8: 2 (mass ratio) 27 g (yield 90%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 2,400 and 1.38, respectively.

Then, the above Poly [NCA: NBD
O] = 8: 2 (mass ratio) was reacted with triethylamine and chloromethylethyl ether in THF solvent as in Example 1 to give Poly [NCA: NE].
MC: NBDO] = 1.5: 7.5: 2 (mass ratio) (yield 93%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 3,700 and 1.56, respectively.

Example 3: Poly [NEMC: NBD]
O] = 7: 3 (mass ratio) 5-norbornene-2-carboxylic acid 2 as a synthetic comonomer
1-g and 5-norbornene-2-acquired in the above Production Example 1
Poly [NC] was prepared in the same manner as in Example 1, except that 9 g of butane-1,3-dione was used.
A: NBDO] = 7: 3 (mass ratio) 25.2 g (yield 8)
4%). The weight average molecular weight and the molecular weight distribution of the copolymer were 2,700 and 1.40, respectively.

Then, the above Poly [NCA: NBD
O] = 7: 3 (mass ratio) was reacted with triethylamine and chloromethylethyl ether in THF solvent as in Example 1 to give Poly [NEMC: N].
BDO] = 7: 3 (mass ratio) (yield 95%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 3,500 and 1.49, respectively.

Example 4: Poly [NCA: NEM]
C: NBDO: tBNCL] = 1: 3: 2: 4 (mass ratio), using 0.5 g of palladium chloride as a synthetic polymerization catalyst,
5-norbornene-2-carboxylic acid 2 as a comonomer
0 g, 5-norbornene-2-acquired in the above Production Example 1
Butane-1,3-dione 10 g and t-butoxy-5
-Norbornene-2-carboxylate (hereinafter "tB
NCL ") except that 20g was used,
The same method as in Example 1 was applied to Poly [NCA: N
BDO: tBNCL] = 4: 2: 4 (mass ratio) 45 g
(Yield 90%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 3,000 and 1.47, respectively.

Then, the above Poly [NCA: NBD
O: tBNCL] = 4: 2: 4 (mass ratio),
As in, by reacting with triethylamine and chloromethyl ethyl ether in THF solvent to give Poly
[NCA: NEMC: NBDO: tBNCL] = 1:
3: 2: 4 (mass ratio) (yield 95%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer are 3, 4 respectively.
00 and 1.55.

Example 5: Poly [NCA: NEM
C: NBDO: NB] = 0.5: 5.5: 2: 2 (mass ratio) 5-norbornene-2-carboxylic acid 3 as a comonomer
0 g and 5-norbornene-2-obtained in the above Production Example 1
Poly [NC] was prepared in the same manner as in Example 1, except that 10 g of butane-1,3-dione and 10 g of norbornene (hereinafter referred to as “NB”) were used.
A: NBDO: NB] = 6: 2: 2 (mass ratio) 45 g
(Yield 90%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 3,100 and 1.46, respectively.

Then, the above Poly [NCA: NBD
O: NB] = 6: 2: 2 (mass ratio) was reacted with triethylamine and chloromethylethyl ether in THF solvent as in Example 1 to give Poly [NC
A: NEMC: NBDO: NB] = 0.5: 5.5:
2: 2 (mass ratio) (yield 96%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer are 3,700, respectively.
And 1.66.

Example 6: Poly [NCA: NEM
C: NBDO: tBNCL: NB] = 1: 2: 1: 5:
5-norbornene-2-carboxylic acid 1 as a synthetic comonomer of 1 (mass ratio)
5 g, 5-norbornene-2-obtained in the above Production Example 1
Poly [NCA: NBDO: was obtained in the same manner as in Example 1 except that 5 g of butane-1,3-dione, 25 g of t-butoxy-5-norbornene-2-carboxylate and 5 g of norbornene were used. tBNC
L: NB] = 3: 1: 5: 1 (mass ratio) 45 g (yield 9
0%). The weight average molecular weight and the molecular weight distribution of the copolymer were 3,100 and 1.46, respectively.

Then, the above Poly [NCA: NBD
O: tBNCL: NB] = 3: 1: 5: 1 (mass ratio)
Was reacted with triethylamine and chloromethylethyl ether in THF solvent as in Example 1 to give Poly [NCA: NEMC: NBDO: tBNC.
L: NB] = 1: 2: 1: 5: 1 (mass ratio) (yield 94
%) Was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 3,200 and 1.42, respectively.

Example 7: Poly [NCA: NEM]
C: NBDO: NPDOBO: tBNCL] = 1: 1:
5-Norbornene-2-carboxylic acid 1 as a 2: 3: 3 (mass ratio) synthetic comonomer
0 g, 5-norbornene-2 obtained in the above Production Example 1
-Butan-1,3-dione 10 g, 5-norbornene-2-{(3-propylenedioxy) -butan-1-one} 15 g and t-butoxy-5-norbornene-obtained in the above Production Example 3-1. Poly [NCA: NBDO: NPDOBO: tB was prepared in the same manner as in Example 1 except that 15 g of 2-carboxylate was used.
NCL] = 2: 2: 3: 3 (mass ratio) 45 g (yield 90
%) Was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 2,900 and 1.37, respectively.

Then, the above Poly [NCA: NBD
O: NPDOBO: tBNCL] = 2: 2: 3: 3 (mass ratio) was reacted with triethylamine and chloromethylethyl ether in THF solvent as in Example 1 to give Poly [NCA: NEMC: NBDO: N
PDOBO: tBNCL] = 1: 1: 2: 3: 3 (mass ratio) (yield 90%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 3,100 and 1.3, respectively.
It was 9.

Example 8: Poly [NBDO: NED
OBO: tBNCL] = 2: 6: 2 (mass ratio) under a synthetic nitrogen atmosphere, 0.3 g of palladium chloride was added to water: TH.
After being dissolved in 15 g of a mixed solvent of F = 1: 1, t-butoxy-5-norbornene-comonomer was added to this solution.
6 g of 2-carboxylate and 5 obtained in Production Example 2 above
18 g of norbornene-2- (3-ethylenedioxy) -butan-1-one and 5-acquired in Preparation Example 1
After adding 6 g of norbornene-2-butane-1,3-dione, the pressure inside the reactor was reduced and the reaction was carried out at 40 ° C. for 24 hours. After the reaction was completed, the reaction solution was diluted with an appropriate amount of THF solvent to remove the palladium catalyst and then stirred for about 5 hours while bubbling hydrogen gas, and the black precipitate formed at this time was filtered. Removed.
The filtrate was poured into distilled water for precipitation, followed by filtration and drying to obtain a target copolymer (yield 90%). The weight average molecular weight and the molecular weight distribution of the copolymer were 2,800 and 1.4, respectively.

Example 9: Poly [NBDO: NPD]
OBO: NB] = 2: 7: 1 (mass ratio) as a comonomer, norbornene 3 g, and 5-norbornene-2-{(3-propylenedioxy) -butane-1-obtained in Production Example 3 above. On} 21 g and the target copolymer in the same manner as in Example 8 except that 6 g of 5-norbornene-2-butane-1,3-dione obtained in Production Example 1 was used. (Yield 87%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 2,900 and 1.38, respectively.

Example 10: Poly [NBDO: ND
MPDOBO: tBNCL: NB] = 3: 2: 4: 1
(Mass ratio) as a comonomer, norbornene 3 g, t-butoxy-5-
12 g of norbornene-2-carboxylate, 5-norbornene-2-{(2 ′, 2 ′) obtained in Production Example 4 above.
-Dimethyl-3-propylenedioxy) -butane-1-
On} 6g, and the same method as in Example 8 except that 9 g of 5-norbornene-2-butane-1,3-dione obtained in Production Example 1 was used. Coalescence (yield 85%) was obtained. The weight average molecular weight and the molecular weight distribution of the copolymer were 3,300 and 1.5, respectively.

Example 11: Production of photoresist composition and pattern formation 1 g of each of the copolymers obtained in Examples 1 to 10 and 0.02 g of triphenylsulfonium trifluoromethanesulfonate as a photoacid generator were added to propylene glycol methyl. After being dissolved in 7 g of ether acetate, filtered with a 0.1 μm filter, the filtrate was spin-coated on a silicon wafer, and then prebaked for 60 seconds on a high-temperature substrate at 120 ° C. to form a 0.4 μm-thick photoresist. I got a film. The film was 193 nm (NA 0.
7) Exposure to 24 mJ / cm ² with exposure equipment and 60 at 120 ° C
After heating for 2 seconds, the mixture is treated with a 2.38 mass% TMAH aqueous solution to give
Immersion for 0 seconds and development were performed to obtain a positive pattern with a resolution of 0.11 μm L / S. The positive type pattern formed in this manner had an excellent DOF of 0.5 μm and a dose margin of ± 2 mJ.

[0085]

As described above, the copolymer of the present invention not only has high transparency and etching resistance at 193 nm, but also has a remarkable dissolution rate in exposed and non-exposed areas due to its pKa control. The resolution can be increased by the difference, and since it has a highly hydrophilic diketone functional group, it exhibits excellent substrate adhesion. Therefore, the copolymer of the present invention can be used very effectively as a photoresist material for ArF to provide an excellent semiconductor device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shin Shigehan             Songpa-gu, Seoul, South Korea ▲ Muro-dong             218-12 (72) Inventor Han Asahi             462-5th generation, Yuminseong-dong, Yuseong, Daejeon, Republic of Korea             So Apartment 111 Building No.602 F-term (reference) 2H025 AA02 AA11 AA14 AB16 AC04                       AC08 AD03 BE00 BE10 BG00                       CB08 CB41 FA10 FA17 FA29                 4C022 GA07                 4H039 CA42 CH00                 4J100 AR11 BA03 BA04 BA11 BA15                       BC08 CA01 CA03 CA04 CA05                       DA36 DA39 DA61 DA65 JA38

Claims (8)

[Claims] 1. A 5-norbornene-2-alkane-1,3-dione derivative represented by the following general formula (1b): [In the formula, R ₁ is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms; R ₂ is a hydrogen atom, or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms. And
R ₃ , R ₄ and R ₅ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms,
₁ and R ₅ can be linked to each other to form a cyclic diketone; R ₆ and R ₇ are each independently an alkyl group having 1 to 6 carbon atoms and can be linked to each other to form a ring; 0 to
It is an integer of 6. ] 2. A 5-norbornene-2-alkane-1,3 of the following general formula (1a) in the presence of an acid catalyst in an organic solvent.
-The method for producing a 5-norbornene-2-alkane-1,3-dione derivative according to claim 1, comprising a step of transketalizing a dione compound with a cyclic ketal or a cyclic acetal compound. [Chemical 2] [In the formula, R ₁ is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms; R ₂ is a hydrogen atom or 1 carbon atom;
~ 6 linear, branched or cyclic alkyl groups;
R ₃ , R ₄ and R ₅ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and R 3
₁ and R ₅ can be linked together to form a cyclic diketone; p is an integer from 0-6. ] 3. A photoresist coating of the following general formula (3):
Rubornene-based copolymer. [Chemical 3] [In the formula, R₁Is a linear, branched or ring having 1 to 12 carbon atoms
A linear alkyl group; R₂Is a hydrogen atom or 1 carbon atom
~ 6 linear, branched or cyclic alkyl groups;
R₃, R_FourAnd R_FiveAre each independently a hydrogen atom or charcoal.
A linear or branched alkyl group having a prime number of 1 to 6, wherein R
₁And R_FiveCan be linked together to form a cyclic diketone.
Ki; R₆And R₇Are each independently an alkyl group having 1 to 6 carbon atoms.
Group, which can be linked together to form a ring.
P; is an integer of 0 to 6; R₈And R₉Are each German
Vertically, hydrogen atom, or linear or minute with 1 to 10 carbon atoms
A branched alkyl group, or-(CH₂)_qC (O) OR_Ten,
-(CH₂)_q-OR_Ten,-(CH ₂)_q-C (O) R_Ten,
-(CH₂)_q-OC (O) R_Ten,-(CH₂)_q-OC
(O) OR_TenOr- (CH₂)_q-C (O) OCH₂O
R_Ten(Where R_TenIs a hydrogen atom or a C1-10
Is a linear, branched or cyclic alkyl group, and q is 0 to 6
Is an integer. ) And said R₈And R₉Are connected to each other
To form a ring; a, b and c are each
0.01 ≦ a / a + b + c ≦ 0.30, 0 ≦ b / a + b
+ C ≦ 0.50 and 0.20 ≦ c / a + b + c ≦ 0.
A value satisfying 99; l, m and n are independent of each other.
And is 0 or 1. ] 4. The copolymer has a weight average molecular weight of 1,0.
4. The copolymer according to claim 3, which is a polymer of 00 to 300,000. 5. The method for producing a copolymer according to claim 3, which comprises the following steps: (a) dissolving a palladium (II) catalyst as a polymerization catalyst in water or an organic solvent, or a mixed solvent of water and an organic solvent. (B) In the catalyst solution, in addition to the 5-norbornene-2-alkane-1,3-dione compound of the following general formula (1a) and the norbornene derivative of the following general formula (2), the following general formula is selectively used. The step of adding the 5-norbornene-2-alkane-1,3-dione derivative of (1b) as a comonomer and reacting it in an inert gas atmosphere or under reduced pressure: [Chemical 5] [In the formulas (1a) and (1b), R ₁ has ₁ carbon atom.
~ 12 linear, branched or cyclic alkyl groups; R
₂ is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms; R ₃ , R ₄ and R ₅ are each independently a hydrogen atom or a linear group having 1 to 6 carbon atoms. Or a branched alkyl group, wherein R ₁ and R ₅ can be linked to each other to form a cyclic diketone; R ₆ and R ₇ are each independently an alkyl group having 1 to 6 carbon atoms, They can be linked together to form a ring; p is an integer from 0-6. ] [Chemical 6] [Wherein, R ₈ and R ₉ are each independently a hydrogen atom, or a linear or branched alkyl group having 1 to 10 carbon atoms, or — (CH ₂ ) _q C (O) OR ₁₀ , — (CH ₂ ) _q- OR ₁₀ ,
_{- (CH 2) q -C (} O) R 10, - (CH 2) q -OC
_{(O) R 10, - (} CH 2) q -OC (O) OR 10 or -
(CH ₂₎ at _{q -C (O) OCH 2 OR} 10 ( wherein, R ₁₀ is a hydrogen atom or a C 1-10 linear, branched or cyclic alkyl group, q is 0 to 6 integer And R ₈ and R ₉ can be joined together to form a ring. ] 6. The method according to claim 5, wherein the palladium (II) catalyst is represented by the following general formula (4a), (4b) or (4c). [Chemical 7] [Chemical 8] [Chemical 9] [In the formulas (4a) to (4c), X is a halogen atom or an alkyl group having 1 to 10 carbon atoms; R'is an allyl compound having 3 to 20 carbon atoms; R "is a nitrile compound or a cyclodiene compound; Yes; n is 1 or 2
Is. ] 7. A photoresist composition containing (a) the copolymer of claim 3, (b) a photoacid generator, and (c) an organic solvent capable of dissolving the components (a) and (b). . 8. A method of forming a photoresist pattern, comprising the steps of: (a) applying the photoresist composition of claim 7 to the top of an etching layer to form a photoresist film; Pre-baking the photoresist film on a high temperature substrate; (c) placing a mask on the pre-baked photoresist film and then exposing it to a light source having a wavelength of 250 nm or less; (d) Baking the exposed photoresist film on a hot substrate; and (e) developing the baked photoresist film to obtain the desired photoresist pattern.